# 表单数据

接收的不是 JSON，而是表单字段时，要使用 `Form`。

/// info | "说明"

要使用表单，需预先安装 <a href="https://github.com/Kludex/python-multipart" class="external-link" target="_blank">`python-multipart`</a>。

例如，`pip install python-multipart`。

///

## 导入 `Form`

从 `fastapi` 导入 `Form`：

```Python hl_lines="1"
{!../../docs_src/request_forms/tutorial001.py!}
```

## 定义 `Form` 参数

创建表单（`Form`）参数的方式与 `Body` 和 `Query` 一样：

        password: str

    class ModelA(BaseModel):
        name: str
        description: Optional[str] = None
        foo: ModelB

        @field_validator("name")
        def lower_username(cls, name: str, info: ValidationInfo):
            if not name.endswith("A"):
                raise ValueError("name must end in A")
            return name

    async def get_model_c() -> ModelC:

    assert response.json() == {"cls": "B"}


def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "info": {"title": "FastAPI", "version": "0.1.0"},
        "openapi": "3.1.0",
        "paths": {
            "/a": {
                "get": {
                    "operationId": "a_a_get",
                    "responses": {

def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "openapi": "3.1.0",
        "info": {"title": "FastAPI", "version": "0.1.0"},
        "servers": [
            {"url": "/", "description": "Default, relative server"},
            {
                "url": IsOneOf(

app = FastAPI()


@app.get("/a", responses={"hello": {"description": "Not a valid additional response"}})
async def a():
    pass  # pragma: no cover


openapi_schema = {
    "openapi": "3.1.0",
    "info": {"title": "FastAPI", "version": "0.1.0"},
    "paths": {
        "/a": {
            "get": {
                "responses": {
                    # this is how one would imagine the openapi schema to be

log4j.rootLogger=INFO,STDOUT
log4j.appender.STDOUT=org.apache.log4j.ConsoleAppender
log4j.appender.STDOUT.ImmediateFlush=true
log4j.appender.STDOUT.layout=org.apache.log4j.PatternLayout

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	exit 1
fi

if [ $policy_count -ne $expanded_policy_count ]; then
	echo "BUG: original policy count  differs from expanded setup"
	exit 1
fi

./mc version info myminio/versioned | grep -q "versioning is enabled"
ret=$?
if [ $ret -ne 0 ]; then
	echo "expected versioning enabled after expansion"
	exit 1
fi

./mc mirror cmd myminio/versioned/ --quiet >/dev/null

        for (int i = 0; i < size; i++) {
          keys[i] = rng.nextInt();
        }
        return createTreap(Ints.asList(keys));
      }

      // See http://en.wikipedia.org/wiki/Treap for details on the algorithm.
      private Optional<BinaryNode> createTreap(List<Integer> keys) {
        if (keys.isEmpty()) {
          return Optional.absent();
        }
        int minIndex = 0;

* `description`: The description of your API, this can include markdown and will be shown in the docs.
* `routes`: A list of routes, these are each of the registered *path operations*. They are taken from `app.routes`.

/// info

The parameter `summary` is available in OpenAPI 3.1.0 and above, supported by FastAPI 0.99.0 and above.

///

## Overriding the defaults